The N-Terminal GYPSY Motif Is Required for Pilin-Specific Sortase SrtC1 Functionality in Lactobacillus rhamnosus Strain GG |
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| Authors: | Fran?ois P. Douillard Pia Rasinkangas Arnab Bhattacharjee Airi Palva Willem M. de Vos |
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| Affiliation: | 1Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland;2Research Programs Unit Immunobiology, Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland;3Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands;University of Kansas Medical Center, UNITED STATES |
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| Abstract: | Predominantly identified in pathogenic Gram-positive bacteria, sortase-dependent pili are also found in commensal species, such as the probiotic-marketed strain Lactobacillus rhamnosus strain GG. Pili are typically associated with host colonization, immune signalling and biofilm formation. Comparative analysis of the N-terminal domains of pilin-specific sortases from various piliated Gram-positive bacteria identified a conserved motif, called GYPSY, within the signal sequence. We investigated the function and role of the GYPSY residues by directed mutagenesis in homologous (rod-shaped) and heterologous (coccoid-shaped) expression systems for pilus formation. Substitutions of some of the GYPSY residues, and more specifically the proline residue, were found to have a direct impact on the degree of piliation of Lb. rhamnosus GG. The present findings uncover a new signalling element involved in the functionality of pilin-specific sortases controlling the pilus biogenesis of Lb. rhamnosus GG and related piliated Gram-positive species. |
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